Apparatus for, and method of, oxidizing a gaseous mixture containing a combustible component

ABSTRACT

Apparatus for oxidizing a gaseous mixture containing a potentially combustible component includes a combustion chamber for burning and oxidizing a combustible gas, a heated oxidation chamber for heating and oxidizing an incombustible gas, a conduit communicating a source of the gaseous mixture with the combustion and oxidation chambers, and electrically-operable gas valves arranged in the conduit and operable to deliver a flow of the gaseous mixture to either the combustion chamber or to the oxidation chamber. An electrical control circuit is adapted to sense the combustibility of the gaseous mixture. If such mixture is sensed to be incombustible, the control circuit operates the valves to deliver such flow to the oxidation chamber.

United States Patent Huyck APPARATUS FOR, AND METHOD OF, OXIDIZING AGASEOUS MIXTURE CONTAINING A COMBUSTIBLE COMPONENT Inventor: Robert T.Huyck, Kenmore, N.Y.

Assignee: Roberts-Gordon Appliance Corporation, Buffalo, N.Y.

Filed: Oct. 24, 1974 Appl. No.: 517,404

[52] U.S. Cl 431/5; 23/277 C; 431/202 [51] Int. Cl. F23D 13/20 [58]Field of Search 431/5, 202, 2; 23/277 C [56] References Cited UNITEDSTATES PATENTS I 3,741,713 6/1973 Reed 431/202 3,817,687 6/1974Cavallero et al... 431/202 3,837,785 9/1974 Evans et a1. 431/5 PrimaryExaminerEdward G. Favors Attorney, Agent, or Firm-Sommer & Sommer [57]ABSTRACT Apparatus for oxidizing a gaseous mixture containing apotentially combustible component includes a combustion chamber forburning and oxidizing a combustible gas, a heated oxidation chamber forheating and oxidizing an incombustible gas, a conduit communicating. asource of the gaseous mixture with the combustion and oxidationchambers, and electricallyoperable ga's valves arranged in the conduitand operable to deliver a flow of the gaseous mixture to either thecombustion chamber or to the oxidation chamber. An electrical controlcircuit is adapted to sense the combustibility of the gaseous mixture.If such mixture is sensed to be incombustible, the control circuitoperates the valves to deliver such flow to the oxidation chamber.

9 Claims, 2 Drawing Figures HIGH TEMPERATURE 29 5o LIMIT CONTROL HEATSENSOR ELECTRIC HEATER \OXIDATION CHAMBER llllllll FLAME SENSOR PROBEAIR SHUTTER UME-AIR MIXER 4 ELESZRIC GAS VALVE US. Patent Oct. 21, 19753,914,088

COMBUSTION GHAMBER\ ELECTRIC HEATER OXIDATION CHAMBER SPARK GENERATOR iIO IIIIIIIIIH l//FLAME sENsoR PROBE 2O FuME-A|R MIXER 39 32 AIR SHUTTER44 FUME \I INLET 33f 3 35 I5. 56 HOT 7' GROL NO 59 NORMALLY CLOSED ZMANuAL REsET TYPE 60 HIGH TEMPERATURE s5 LIMIT CONTROL 74 5| SPARKGENERATOR 62 79 SPARK GENERATOR 76 --66 2 I4 49 g 52 W 63 ELECTRICHEATER -68 3 FLAME SENSING RELAY HEAT SENSOR i VALVE led APPARATUS FOR,AND METHOD OF, OXIDIZING A GASEOUS MIXTURE CONTAINING A COMBUSTIBLECOMPONENT BACKGROUND OF THE INVENTION 1. Field of the Invention Thepresent invention relates generally to apparatus for oxidizing a gaseousmixture containing a potentially combustible component.

2. Description of the Prior Art Prior art efforts to provide apparatusfor oxidizing a gaseous mixture have begun with the threshold inquiry ofwhether such mixture is combustible or incombustible.

The easiest way to oxidize a combustible gas is to ignite and burn it,as typically shown in Frey et al U.S. Pat. No. 3,697,229, Rosenberg etal U.S. Pat. No. 3,509,834, Chance U.S. Pat. No. 1,298,889, Kuhn U.S.Pat. No. 2,460,016, Stockman U.S. Pat. No. 3,353,919,

and Wilson et al U.S. Pat. No. 3,337,455.

On the other hand, it is known that an incombustible gas may be oxidizedby the influence of heat, this principle being shown in Shiller U.S.Pat. No. 3,404,965, Gerlach U.S. Pat. No. 3,279,168, Phillips U.S. Pat.No. 3,215,501, and Bloxham U.S. Pat. No. 3,190,823.

However, whether a particular gaseous mixture is combustible orincombustible may well depend upon the extent to which a potentiallycombustible component of the mixture is present with a cooperativeamount of oxygen. For example, a particular gaseous mixture composed ofgasoline fumes and air may be either combustible or incombustible,depending upon the relative proportional quantities to which thesecomponents are present in the mixture. Therefore, since theconcentration of a potentially combustible component may vary with anumber of factors, the combustibility of the entire mixture itself mayvary.

SUMMARY OF THE INVENTION The present invention provides apparatus foroxidizing a gaseous mixture containing a potentially combustiblecomponent, regardless of whether such mixture itself is combustible orincombustible. Moreover, the apparatus is particularly designed tooxidize a mixture of varying combustibility.

The apparatus broadly includes a combustion chamber having means forigniting a combustible gas; an oxidation chamber having means forheating and oxidizing an incombustible gas; conduit meanscommunicatively connecting a source of the gaseous mixture with thecombustion and oxidation chambers; valve means associated with theconduit means and operative to block the same to prevent a flow of themixture therethrough, or to alternatively direct such flow to either thecombustion chamber or to the oxidation chamber; and control meansadapted to sense the combustibility of the mixture and tocause the valvemeans to permit and direct such flow to the combustion chamber when themixture is sensed to be combustible, and to deliver such flow to theoxidation chamber when the mixture is sensed to be incombustible.

In one embodiment, the control means includes a first flame sensoroperatively arranged to sense the presence of a flame in the combustionchamber and adapted to cause the valve means to divert such flow to theoxidation chamber when no flame is sensed in the combustion chamber.

The control means may further include igniting means, such as a sparkgenerator, operatively arranged to attempt to ignite the mixturedelivered to the oxidation chamber, and a second flame sensoroperatively arranged to divert such flow to the combustion chamber whenthe presence of a flame is sensed in the oxidation chamber.

The control means may further include means for sensing the effectivetemperature of the oxidation chamber for causing the valve means toprevent such flow from entering the oxidation chamber when thetemperature within the oxidation chamber is below a preselected minimumtemperature.

The inventive apparatus oxidizes a gaseous mixture containing apotentially combustible component by supplying a flow of the mixturefrom a source thereof, sensing the combustibility of the suppliedmixture, diverting the supplied flow to the combustion chamber if themixture is sensed to be combustible, igniting the combustible mixture inthe combustion chamber, diverting such supplied flow to a heatedoxidation chamber if the mixture is sensed to be incombustible, andoxidizing such incombustible mixture inthe oxidation chamber. Inpracticing this method, the combustibility of the mixture is preferrablysensed by determinging the presence or absence of a flame, or the heatthereof.

One object of the present invention is to provide improved apparatus foroxidizing a gaseous mixture containing a potentially combustiblecomponent.

Another object is to provide improved apparatus for oxidizing either acombustible or an incombustible gaseous mixture.

Another object is to provide improved oxidation apparatus whereinthe-combustibility of a supplied gaseous mixture is sensed.

Another object is to provide improved apparatus for, and a method of,oxidizing a gaseous mixture wherein the mixture is oxidized by burningin a combustion chamber if such-mixture is sensed to be combustible, andoxidized in a heated oxidation chamber if such mixture is sensed to beincombustible.

Still another object is to provide improved apparatus capable ofoxidizing a gaseous mixture regardless of the combustibility of themixture.

These and other objects and advantages will become apparent fromtheforegoing and ongoing specification which includes the drawings andthe appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a mechanical schematic viewof the structure of the apparatus, principally illustrating thecombustion and oxidation chambers, the conduit arranged to deliver aflow of the gaseous mixture to the combustion and oxidation chambers,the valves associated with the branch conduits, and the location of theflame sensor probes, the heat sensor switch, and the high temperaturelimit control switch.

FIG. 2 is an electical schematic view of the circuitry of the invention,illustrating the arrangement of the spark generators, the electricheater, and further showing the flame sensing relay arranged to controloperation of the valves.

DESCRIPTION OF THE PREFERRED EMBODIMENT At the outset, it should beclearly understood that like reference numerals are intended to identifythe same elements and/or structure throughout the several drawingfigures, as such elements and/or structure may be further described orexplained by the entire written specification of which this detaileddescription is an integral part.

Referring initially to FIG. 1, the present invention provides apparatus,generally indicated at 10, for oxidizing a gaseous mixture containing apotentially combustible component, such as gasoline fumes, and flowingfrom a source (not shown) thereof.

As used herein, a potentially combustible component is intended broadlyto refer to any gaseous fluid which, when mixed with the proper amountof oxygen, is capable of burning when ignited. However, since suchpotentially combustible components may be present in gaseous mixtures invarying fractional degrees, it should be clearly understood thatcombustibility of such mixtures, as a whole, may vary. Hence, somemixtures may be combustible, while others may be incombustible.

The apparatus broadly includes a combustion chamber 11 having means,generally indicated indicated at 12, for igniting a flow of combustiblegas delivered to the combustion chamber; an oxidation chamber 13 havingmeans, generally indicated at 14, for heating and oxidizing a flow ofincombustible gas rising through the oxidation chamber; conduit means 15communicatively connecting a source (not shown) of the gaseous mixturewith the combustion chamber 11 and with the oxidation chamber 13; valvemeans, generally indicated at 16, associated with the conduit means 15and operative to selectively block and prevent a flow of the. gaseousmixture through the conduit means, or to alternatively permit and divertsuch flow to either the combustion chamber 11 or to the oxidationchamber 13; and control means, generally indicated at 18 in FIG. 2,adapted to sense the combustibility of the gaseous mixture flowingthrough the conduit means 15 and to cause the valve means 16 to directsuch flow to the combustion chamber 11 when such mixture is sensed to becombustible, and to divert such flow to the oxidation chamber 13 whensuch mixture is sensed to be incombustible.

Adverting now to FIG. 1, the combustion and oxidation chambers 11, 13are schematically depicted as contained within an enclosure 19 having ahorizontal bottom 20, and a vertical side wall structure 21 risingupwardly therefrom. Side wall structure 21 is shown provided with anopen upper end suitably covered by an overhead inverted hopper-like hoodstructure 22 which functions to direct or funnel the rising flow ofgaseous products of combustion and oxidation, such as carbon dioxide (COand water vapor, (H O), upwardly away from the combustion and oxidationchambers 11, 13 and from enclosure 19.

Arranged within this enclosure 19, the combustion and oxidation chambers11, 13 are depicted as bounded by a pair of laterally-adjacent left andright open-ended vertical tubes 23, 24 respectively, sharing anintermediate common wall 25. The leftward tube 23, bounding thecombustion chamber 11, is specifically shown as having upper and loweropen ends 26,

28, respectively. Similarly, the rightward tube 24, boundingtheoxidation chamber 13 is also shown as having upper and lower openends 29, 30, respectively. If desired, the vertical tubular walls 23, 24and 25 may be made of a suitable thermal insulating or refractorymaterial, as depicted in FIG. 1.

In the presently preferred embodiment herein disclosed, the means 14 forheating and oxidizing a gas delivered to the oxidation chamber isschematically shown as including an electrical resistance-type heatingelement 31 suitably mounted within right tube 24 to heat the oxidationchamber. When energized, this heating element 31 operates to elevate thetemperature of a gas rising through oxidation tube 24 to oxidize suchrising gas and to. reduce hydrocarbons therein to carbon dioxide (CO andwater vapor (H O).

The conduit means 15 is shown as including a main supply conduit 32communicating the source (not shown) of the gaseous mixture with a firstbranch conduit 33 leading to the combustion chamber 11, and with asecond branch conduit 34 leading to the oxidation chamber 13. The firstbranch conduit 33 includes,

in series, pipe conduit 35 communicating with supply conduit 32,electrically-operable gas valve 36, pipe conduit 38, air shutter 39, andgas burner 40 mounted to penetrate the enclosure bottom 20 and having anup permost perforated burner head 41 arranged beneath.

the combustion chamber 11. Similarly, the second branch conduit 34includes, in series, pipe conduit 42 communicating with supply conduit32 electricallyoperable gas valve 43, pipe conduit 44, air shutter 45,

and gas burner 46 mounted to penetrate the enclosure.

bottom 20 and having an uppermost perforated burner head 48 arrangedbeneath the oxidation chamber 13.

Thus, the conduit means 15, which includes the first and second branchconduits, 33, 34, respectively, cornmunicatively connects the source(not shown) of the mixture with the combustion chamber 11 and with {theoxidatin chamber 13.

In the presently preferred embodiment, the means 12 for igniting acombustible gas is shown as being a conventional spark generatoroperatively arranged between burner head 41 and the lower open end 28 ofcombustion chamber 11 to attempt to ignite gas rising upwardly fromburner head 41.

The valve means 16 includes electrically-operated gas valves 36, 43,arranged in the first and second branch conduits 33, 34, respectively.Each of valves 36,.

43 may be selectively operated by the control means 18 to block itsassociated branch conduit to prevent the gaseous mixture from flowingfrom the source (not shown) to its serviced burner, or to alternativelyunblock its associated branch conduit toenable such flow. Hence, ifvalve 36 is opened and valve 43 is: closed, the gaseous mixture will bepermitted to flow from the source through the main supply conduit 32 andthe first branch conduit 33 to the combustion chamber 11.. Conversely,if valve 36 is closed and valve 43 is opened, the gaseous mixture willbe permitted to flow from the source through the main supply conduit 32and the second branch conduit 34 to the oxidation chamber 13. Thus, byselectively closing one of these valves and opening the other, the valvemeans16 functions to permit and direct such flow to either thecombustion chamber or to the oxidation chamber. Obviously, if gas valves36, 43 are both closed, the conduit means 15 will be blocked to preventsuch flow to either the combustion chamber 11 or the oxidation chamber13. It should be clearly understood that in lieu of providing a separatevalve in each branch conduit, a single three-way valve, capable ofperforming the same functions as valves 36, 43 may be arranged at thejuncture of the main supply conduit 32 with the first and second branchconduits, 33, 34, respectively.

Referring now conjunctively to FIGS. 1 and 2, the control means 18broadly includes igniting means, such as spark generator 49, arrangedbetween the oxidation chamber lower end 30 and burner head 48, heatsensor switch 50 and high temperature limit control switch 51 mounted onenclosure side wall 21 and operatively arranged above the oxidationchamber 13, and a flame sensing relay 52 having flame sensor probes 53,54 arranged above the combustion chamber burner head 41 v and theoxidation chamber burner head 48, respectively (FIG. 1).

Adverting now to FIG. 2, the electrical circuitry of the apparatus isschematically depicted as broadly including manual on-off switch 55;high temperature limit control switch 51', spark generators 12, 49;electrical heater 14; flame sensing relay 52; heat sensor switch 50; andelectrically-operable gas valves 36, 43.

An input voltage applied across circuit input terminals 56, 58 willproduce a like potential between a hot wire connected to circuitterminal 56, and a ground wire connected to circuit terminal 58. Thishot wire includes, in series: conductor 59 connected to circuit inputterminal 56; manual switch 55 when in the closed position; conductor60', normally closed (N/C) high temperature limit control switch 51, andconductors 61, 62, 63 and 64. The ground wire includes, in series:conductor 65 connected to circuit input terminal 58, conductors 66, 68,69 and 70, and grounded conductor 71.

When switches 55 and 51 are both closed, current may flow through aplurality of parallel circuits severally connected to the hot wire andto the ground wire. Specifically, current may flow from hot wireconductor 61 through a first parallel circuit containing conductor 72; afirst branch circuit containing, in series, conductor 73, sparkgenerator 12, and conductor 74; a second branch circuit arranged inparallel with the first branch circuit and including, in series,conductor 75, spark generator 49, and conductor 76; and conductor 78connected to ground wire conductor 65.

Current may also flow from hot wire conductor 62 through a secondparallel circuit containing, in series, conductor 79, resistance heater14, and conductor 80 connected to ground wire conductor 66.

Current may also flow from hot wire conductor 63 through a thirdparallel circuit containing, in series, conductor 81, flame sensingrelay 52, and conductor 82 connected to ground wire conductor 68.

Current may also flow from hot wire conductor 64 through a fourthparallel circuit containing, in series, conductor 83; flame sensorcontrolled switch 84; a third branch circuit including, in series,conductor 85, heat sensor switch 50 when closed, conductor 86, solenoidvalve 43, and conductor 88 connected to ground wire conductor 69; and afourth branch circuit arranged in parallel with the third branch circuitand including, in series, conductor 89, solenoid valve 36, and conductor90 connected to ground wire conductor 70.

OPERATION To operate the apparatus 10 from a deactivated condition,manual switch 55 must first be closed to energize the several parallelcircuits. When this switch has been closed, current may flow from thehot wire to the ground wire through spark generators 12, 49; electricheater l4; and flame sensing relay 52. However, since a no flamecondition will be initially sensed in the combustion chamber by flamesensor probe 53, relay 52 will cause switch 84 to move to the positionshown in solid in FIG. 2, thereby attempting to operate valve 43 todeliver a flow of the gaseous mixture to the oxidation chamber 13.

Heat sensor switch 50 determines when resistance heater 14 has heatedthe oxidation chamber 13 to its preselectedoperating temperature capableof oxidizing the gaseous mixture, and thereafter closes to complete thecircuit including valve 43 to operate this valve and enable a flow ofthe gaseous mixture to the oxidation chamber 13 through the secondbranch conduit 34.

When such flow of the gaseous mixture in second branch conduit 34 passesupwardly through burner head 48, spark generator 49 attempts to ignitethe mixture. If the mixture is incombustible, such mixture will not beignited and a no flame condition in the oxidation chamber 13 will besensed by flame sensor probe 54. This condition is transmitted via flamesensing relay 52 to maintain switch 84 in its present position, allowinga continued flow of the incombustible gaseous mixture to pass throughthe second branch conduit and rise upwardly through burner head 48 tothe oxidation chamber. During its ascent through the heated oxidationchamber, this incombustible gaseous mixture is oxidized under theinfluence of heat supplied by heater 14. I Should the gaseous mixturedelivered to the oxidation chamber become combustible, spark generator49 will ignite the mixture and flame sensing probe 54 will then sense aflame? condition in the oxidation chamber. Should this occur, flamesensing relay 52 will cause switch 84 to move to the phantom positiondepicted in FIG. 2, thereby deenergizing and closing valve 43 to blockthe first branch conduit 34, and energizing and opening valve 36. Whenvalve 36 has opened, the gaseous mixture will be permitted to flow fromthe source thereof through the first branch conduit 33 to the combustionchamber 11 wherein such combustible gaseous 7 mixture rising throughburner head 41 will be ignited by spark generator 12. This combustiblegas will be continuously supplied to the combustion chamber as long asflame sensor probe 53 senses the presence of a flame in the combustionchamber.

Should the gaseous mixture then become incombustible, a no flamecondition will be sensed by flame sensor probe 53. When this occurs,flame sensing relay 52 will cause switch 84 to revert to the solidposition depicted in FIG. 2, thereby deenergizing and closing valve 36,and energizing and opening valve 43 to divert the flow of the gaseousmixture from the combustion chamber to the oxidation chamber.

The normally-closed high temperature limit control switch 51 is providedas an additional safety feature. Should the temperature in oxidationchamber 13 exceed a preselected maximum temperature, as by sustainedcombustion of the gaseous mixture in the oxidation chamber, switch 51will automatically open to disconnect the electrical circuit of theapparatus from the input terminal 56, thereby deenergizing the apparatusand closing valves 36, 43.

In this manner, the inventive apparatus 10 operates to sense ordetermine the combustibility of the gaseous mixture flowing through theconduit means, and to deliver such flow to the oxidation chamber if suchmixture is sensed to be incombustible, and to deliver such mixture tothe combustion chamber if such mixture is sensed to be combustible. Itwill be noted by those skilled in this art that after the oxidationchamber has been heated to its operating temperature, the control meanswill automatically divert the flow of the gaseous mixture to either thecombustion chamber or the oxidation chamber in response to the sensedcombustibility of the mixture.

The several mechanical and electrical components of the inventiveapparatus are well known to those skilled in this art and need not bespecifically described. However, it is contemplated that sparkgenerators 12, 49 may operate either continuously or intermittently, asdesired.

While a preferred embodiment of the present inventionhas been shown anddescribed herein, it will be understood by those skilled in this artthat various changes and modifications may be made without departingfrom the spirit of the invention which is defined by the followingclaims.

What is claimed is:

1. Apparatus for oxidizing a gaseous mixture containing a potentiallycombustible component and flowing from a source thereof, comprising:

a combustion chamber having means for igniting a combustible gasdelivered thereto;

an oxidation chamber having means for heating and oxidizing a gasdelivered thereto;

conduit means communicatively connecting said source with saidcombustion and oxidation chambers;

valve means associated with said conduit means and operative to blocksaid conduit means to prevent said flow and to permit and direct saidflow to either said combustion chamber or to said oxidation chamber;

control means adapted to sense the combustibility of said mixture and tocause said valve means to direct said flow to said combustion chamberwhen said mixture is sensed to be combustible, and to deliver said flowto said oxidation chamber when said mixture is sensed to beincombustible.

2. The apparatus according to claim 1 wherein said control meansincludes a first flame sensor operatively arranged to sense the presenceof a flame in said combustion chamber for causing said valve means todivert said flow to said oxidation chamber when no flame is sensed insaid combustion chamber.

3. The apparatus according to claim 1 wherein said control meansincludes igniting means operatively arranged to attempt to ignite saidmixture delivered to said oxidation chamber, and a second flame sensoroperatively arranged to cause said valve means todirect said flow tosaid combustion chamber when a flame is sensed in said oxidationchamber.

4. The apparatus according to claim 1 wherein said control meansincludes a first flame sensor operatively arranged to sense the presenceof a flame in said combustion chamber for causing said valve means todivert said flow to said oxidation chamber when no flame is sensed insaid combustion chamber, igniting means operatively arranged to attemptto ignite said mixture delivered to said oxidation chamber, and a secondflame sensor operatively arranged for causing said valve means to directsaid flow to said combustion chamber when a flame is sensed in saidoxidation chamber.

5. The apparatus according to claim 1 wherein said control means furtherincludes a temperature switch for sensing the temperature of saidoxidation chamber and for causing said valve means to prevent said flowfrom entering said oxidation chamber when the temperature of saidoxidation chamber is below a preselected minimum temperature 6. Theapparatus according to claim 4 wherein said control means furtherincludes a temperature switch for sensing the temperature of saidoxidation chamber and for causing said valve means to prevent said flowfrom entering said oxidation chamber when the temperature of saidoxidation chamber is below a preselected minimum temperature.

7. The method of oxidizing a gaseous mixture containing a combustiblecomponent, comprising the steps of:

supplying a flow of said mixture from a source thereof;

sensing the combustibility of such supplied mixture;

delivering such supplied flow to a combustion chamber if said mixture issensed to be combustible; igniting and burning such mixture in saidcombustion chamber;

delivering such supplied flow to heated oxidation chamber if saidmixture is sensed to be incombustible; and

oxidizing such incombustible mixture in said oxidation chamber.

8. The method according to claim 7 wherein the step of sensing thecombustibility of such supplied mixture, includes the further steps of:

attempting to ignite said mixture; and

determining the presence of a flame produced by such ignited mixture.

9. The method according to claim 7 wherein the step of delivering suchsupplied flow to an oxidation chamber if said mixture is sensed to beincombustible includes the further step of:

admitting said incombustiblemixture to said oxidation chamber only whenthe temperature of said temperature.

1. Apparatus for oxidizing a gaseous mixture containing a potentiallycombustible component and flowing from a source thereof, comprising: acombustion chamber having means for igniting a combustible gas deliveredthereto; an oxidation chamber having means for heating and oxidizing agas delivered thereto; conduit means communicatively connecting saidsource with said combustion and oxidation chambers; valve meansassociated with said conduit means and operative to block said conduitmeans to prevent said flow and to permit and direct said flow to eithersaid combustion chamber or to said oxidation chamber; control meansadapted to sense the combustibility of said mixture and to cause saidvalve means to direct said flow to said combustion chamber when saidmixture is sensed to be combustible, and to deliver said flow to saidoxidation chamber when said mixture is sensed to be incombustible. 2.The apparatus according to claim 1 wherein said control means includes afirst flame sensor operatively arranged to sense the presence of a flamein said combustion chamber for causing said valve means to divert saidflow to said oxidation chamber when no flame is sensed in saidcombustion chamber.
 3. The apparatus according to claim 1 wherein saidcontrol means includes igniting means operatively arranged to attempt toignite said mixture delivered to said oxidation chamber, and a secondflame sensor operatively arranged to cause said valve means to directsaid flow to said combustion chamber when a flame is sensed in saidoxidation chamber.
 4. The apparatus according to claim 1 wherein saidcontrol means includes a first flame sensOr operatively arranged tosense the presence of a flame in said combustion chamber for causingsaid valve means to divert said flow to said oxidation chamber when noflame is sensed in said combustion chamber, igniting means operativelyarranged to attempt to ignite said mixture delivered to said oxidationchamber, and a second flame sensor operatively arranged for causing saidvalve means to direct said flow to said combustion chamber when a flameis sensed in said oxidation chamber.
 5. The apparatus according to claim1 wherein said control means further includes a temperature switch forsensing the temperature of said oxidation chamber and for causing saidvalve means to prevent said flow from entering said oxidation chamberwhen the temperature of said oxidation chamber is below a preselectedminimum temperature.
 6. The apparatus according to claim 4 wherein saidcontrol means further includes a temperature switch for sensing thetemperature of said oxidation chamber and for causing said valve meansto prevent said flow from entering said oxidation chamber when thetemperature of said oxidation chamber is below a preselected minimumtemperature.
 7. THE METHOD OF OXIDING A GASEOUS MIXTURE CONTAINING ACOMBUSTIBLE COMPONENT, COMPRISING THE STEPS OF: SUPPLYING A FLOW OF SAIDMIXTURE FROM A SOURCE THEROF, SENSING THE COMBUSTBILIY OF SUCH SUPPLIEDMIXTURE, DELIVERING SUCH SUPPLIED FLOW TO A COMBUSTION CHAMBER IF SAIDMIXTURE IS SENSED TO BE COMBUSTIBLE, IGNITING AND BURNING SUCH MIXTUREIN SAID COMBUSION CHAMBER, DELIVERING SUCH SUPPLIED FLOW TO HEATEDOXIDATION CHAMBER IF SAID MIXTURE IS SENSED TO BE INCOMBUSTIBLE, AND 8.The method according to claim 7 wherein the step of sensing thecombustibility of such supplied mixture, includes the further steps of:attempting to ignite said mixture; and determining the presence of aflame produced by such ignited mixture.
 9. The method according to claim7 wherein the step of delivering such supplied flow to an oxidationchamber if said mixture is sensed to be incombustible includes thefurther step of: admitting said incombustible mixture to said oxidationchamber only when the temperature of said oxidation chamber exceeds apreselected minimum temperature.